Your network contains a server named Server1 that has Microsoft SharePoint Foundation 2010 installed.
You install the SMTP Server feature on Server1.
You configure the incoming email settings from Central Administration.
You mailenable a document library.
From an external email account, you attempt to send an email message to the document library and you receive a nondelivery report (NDR).
You need to ensure that you can send email messages to the document library.
What should you do?